1. Field of the Invention
The present invention relates to systems and methods for performing opening wedge osteotomies. More specifically, the present invention relates to opening wedge osteotomy systems, and pre-packaged bone graft sets for packing into an osteotomy defect to promote healing, for performing opening wedge osteotomies.
2. Description of the Related Art
Treatment of pain and/or instability associated with lower extremity misalignment may require surgical interventions that include osteotomy. High tibial osteotomies (HTO) are indicated by early, medial joint-space narrowing, by early arthritis in patients who have had previous medial meniscectomy, or following rupture of the anterior cruciate ligament (ACL) in patients with pre-existing varus deformity, for example.
Opening wedge osteotomy procedures are disclosed in U.S. Pat. No. 5,620,448 issued Apr. 15, 1997, and U.S. Pat. No. 5,749,875 issued May 12, 1998, the disclosures of which are incorporated herein by reference.
The known procedures could benefit from advancements in techniques, instrumentation, and materials to make the results more reproducible and reliable.
The present invention provides an improved system for performing the opening wedge osteotomy procedure. The system includes pre-packaged bone graft wedges for packing the osteotomy site. In addition, advanced instrumentation for performing the surgery is provided.
A preferred method of correcting a deformity in a patient by performing an osteotomy in a bone at an osteotomy site uses a bone plate having a projection that is inserted into the osteotomy defect, as described more fully below. Wedges of bone graft material are packed into the defect opening to promote healing and reliability of the repair.
The bone graft material preferably is provided in a three piece, prepackaged set. The bone graft material preferably is either allograft bone, or synthetic bone. A preferred synthetic bone material is made up of either tricalcium phosphate (TCP) or hydroxyapatite (HA), combined with a biodegradable polymer, preferably a polylactide, such as PLA.
The three-piece set includes a smaller, inner piece, and two larger outer pieces. The inner piece is made up of cancellous bone or a synthetic substitute. The outer pieces have inner portions made of the same material as the smaller inner piece, and also have an outer surface that is mostly cortical bone or a synthetic substitute. When using allograft bone, the harvested bone is freeze dried. The prepackaged pieces can by trimmed to shape for the osteotomy by the surgeon.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.